StringDictionary.ContainsValue(String) Metode

Definisi

Ruang nama:

System.Collections.Specialized

Rakitan:

System.Collections.Specialized.dll

Sumber:

StringDictionary.cs

Menentukan apakah StringDictionary berisi nilai tertentu.

public:
 virtual bool ContainsValue(System::String ^ value);

public virtual bool ContainsValue (string? value);

abstract member ContainsValue : string -> bool
override this.ContainsValue : string -> bool

Public Overridable Function ContainsValue (value As String) As Boolean

Parameter

value

String

Nilai untuk ditemukan di StringDictionary. Nilainya bisa .null

Mengembalikan

Boolean

trueStringDictionary jika berisi elemen dengan nilai yang ditentukan; jika tidak, false.

Contoh

Contoh kode berikut mencari elemen dalam StringDictionary.

#using <System.dll>

using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;
void PrintKeysAndValues( StringDictionary^ myCol )
{
   Console::WriteLine( "   KEY        VALUE" );
   IEnumerator^ enum0 = myCol->GetEnumerator();
   while ( enum0->MoveNext() )
   {
      DictionaryEntry^ de = safe_cast<DictionaryEntry^>(enum0->Current);
      Console::WriteLine( "   {0,-10} {1}", de->Key, de->Value );
   }

   Console::WriteLine();
}

int main()
{
   
   // Creates and initializes a new StringDictionary.
   StringDictionary^ myCol = gcnew StringDictionary;
   myCol->Add( "red", "rojo" );
   myCol->Add( "green", "verde" );
   myCol->Add( "blue", "azul" );
   
   // Displays the values in the StringDictionary.
   Console::WriteLine( "Initial contents of the StringDictionary:" );
   PrintKeysAndValues( myCol );
   
   // Searches for a key.
   if ( myCol->ContainsKey( "red" ) )
      Console::WriteLine( "The collection contains the key \"red\"." );
   else
      Console::WriteLine( "The collection does not contain the key \"red\"." );

   Console::WriteLine();
   
   // Searches for a value.
   if ( myCol->ContainsValue( "amarillo" ) )
      Console::WriteLine( "The collection contains the value \"amarillo\"." );
   else
      Console::WriteLine( "The collection does not contain the value \"amarillo\"." );

   Console::WriteLine();
}

/*
This code produces the following output.

Initial contents of the StringDictionary:
   KEY        VALUE
   green      verde
   red        rojo
   blue       azul

The collection contains the key "red".

The collection does not contain the value "amarillo".

*/

using System;
using System.Collections;
using System.Collections.Specialized;

public class SamplesStringDictionary  {

   public static void Main()  {

      // Creates and initializes a new StringDictionary.
      StringDictionary myCol = new StringDictionary();
      myCol.Add( "red", "rojo" );
      myCol.Add( "green", "verde" );
      myCol.Add( "blue", "azul" );

      // Displays the values in the StringDictionary.
      Console.WriteLine( "Initial contents of the StringDictionary:" );
      PrintKeysAndValues( myCol );

      // Searches for a key.
      if ( myCol.ContainsKey( "red" ) )
         Console.WriteLine( "The collection contains the key \"red\"." );
      else
         Console.WriteLine( "The collection does not contain the key \"red\"." );
      Console.WriteLine();

      // Searches for a value.
      if ( myCol.ContainsValue( "amarillo" ) )
         Console.WriteLine( "The collection contains the value \"amarillo\"." );
      else
         Console.WriteLine( "The collection does not contain the value \"amarillo\"." );
      Console.WriteLine();
   }

   public static void PrintKeysAndValues( StringDictionary myCol )  {
      Console.WriteLine( "   KEY        VALUE" );
      foreach ( DictionaryEntry de in myCol )
         Console.WriteLine( "   {0,-10} {1}", de.Key, de.Value );
      Console.WriteLine();
   }
}

/*
This code produces the following output.

Initial contents of the StringDictionary:
   KEY        VALUE
   green      verde
   red        rojo
   blue       azul

The collection contains the key "red".

The collection does not contain the value "amarillo".

*/

Imports System.Collections
Imports System.Collections.Specialized

Public Class SamplesStringDictionary   

   Public Shared Sub Main()

      ' Creates and initializes a new StringDictionary.
      Dim myCol As New StringDictionary()
      myCol.Add("red", "rojo")
      myCol.Add("green", "verde")
      myCol.Add("blue", "azul")

      ' Displays the values in the StringDictionary.
      Console.WriteLine("Initial contents of the StringDictionary:")
      PrintKeysAndValues(myCol)

      ' Searches for a key.
      If myCol.ContainsKey("red") Then
         Console.WriteLine("The collection contains the key ""red"".")
      Else
         Console.WriteLine("The collection does not contain the key ""red"".")
      End If
      Console.WriteLine()

      ' Searches for a value.
      If myCol.ContainsValue("amarillo") Then
         Console.WriteLine("The collection contains the value ""amarillo"".")
      Else
         Console.WriteLine("The collection does not contain the value ""amarillo"".")
      End If
      Console.WriteLine()

   End Sub

   Public Shared Sub PrintKeysAndValues(myCol As StringDictionary)
      Dim de As DictionaryEntry

      Console.WriteLine("   KEY        VALUE")
      For Each de In  myCol
         Console.WriteLine("   {0,-10} {1}", de.Key, de.Value)
      Next de
      Console.WriteLine()

   End Sub

End Class


'This code produces the following output.
'
'Initial contents of the StringDictionary:
'   KEY        VALUE
'   green      verde
'   red        rojo
'   blue       azul
'
'The collection contains the key "red".
'
'The collection does not contain the value "amarillo".

Keterangan

Nilai elemen StringDictionary dibandingkan dengan nilai yang ditentukan menggunakan Object.Equals metode .

Metode ini melakukan pencarian linier; oleh karena itu, waktu eksekusi rata-rata sebanding dengan Count. Artinya, metode ini adalah operasi O(n), di mana n adalah Count.

Dimulai dengan .NET Framework 2.0, metode ini menggunakan objek Equals dan CompareTo metode item koleksi untuk menentukan apakah item ada. Dalam versi .NET Framework sebelumnya, penentuan ini dibuat dengan menggunakan Equals metode item dan CompareTo parameter pada objek dalam koleksi.

Lihat juga

• Melakukan Operasi String Culture-Insensitive